When configuring multiple VLANs on a switch, which OSI model layer is being utilized?

The correct choice relates to Layer 2 of the OSI model, which is the Data Link layer. When configuring multiple VLANs (Virtual Local Area Networks) on a switch, you are primarily dealing with Layer 2 functions. VLANs work by segmenting a single physical network into multiple logical networks, allowing for improved network organization, security, and management.

At Layer 2, VLANs utilize Ethernet frame tagging (such as IEEE 802.1Q) to identify which VLAN a frame belongs to as it traverses the network. This allows switches to handle traffic appropriately based on VLAN membership, effectively segregating broadcast domains and managing traffic flow within a network.

Layer 3, on the other hand, pertains to network routing and is responsible for IP addressing, routing, and forwarding. While it is possible to configure VLANs and utilize Layer 3 functionalities to route between those VLANs, the foundational work of configuring and managing VLANs themselves is rooted at Layer 2. Layers 4 and 5 deal with transport and session management, respectively, and are not involved in VLAN configuration processes.